In contrast with the white kaolin clay, ndimba cannot be found as such in nature: clumps of black river clay (kala tuma) are burned in an open fire until they turn red.
An extensive residue of white kaolin clay pigment is preserved on the exterior surface, which also exhibits extensive striations and wear, apparently the result of the processing and working of the pigment on the dish.
They also noted that much kaolin is in or near decomposed porphyry bodies that overlie the largest ore shoots in the Leadville Dolomite.
A mixture of 33% kaolin and 67% fine sand by dry weight was used to prepare the K33 soil specimen.
He limits himself to a few colors, employing the off-white of kaolin and such dark earth tones as red, brown and black in his allover, schematic compositions.
The white kaolin clay has extra fine particles that simultaneously thwart insects and act as an alkaline barrier to fungal spores.
Surprisingly, many of these are inorganic minerals; for example talc and kaolin or china clay.
But the fine, white clay called kaolin was essential.
Other talc alternatives include slippery elm bark, kaolin clay and bentonite clay.
They were the first to use kaolin clay for porcelains, so that when thin enough, the walls revealed breathtaking translucency.